Computing devices are often shared between multiple users. It is common for a parent who has a computing device to let at least one child use the device. Sometimes, a parent may desire to prevent the child from using certain applications or a certain portion of an application. For example, the parent might have important information in his/her email or banking applications such that he/she does not want to give the child access to those applications. In another example, the parent might let the child browse an Internet electronic market, but might not want the child to buy anything. In a further example, the parent might want the child to only use educational and productive applications, but not play any games; in other words, the parent wants to allow the child to use only a few applications (e.g., educational, productive) but not others (e.g., games). In a further example, the computing device can be shared between two (or more) friends or mere acquaintances. However, conventional approaches typically need for each user of a computing device to sign up for a profile/account so that usage controls, parental controls, etc. can be managed. Moreover, each time a user wants to use another user's device, the former has to sign in again. This can be cumbersome, slow, and inefficient. Accordingly, there needs to be an improved approach to sharing devices and controlling permissions.